(a) Field of the Invention
The present invention relates to a low magnification objective lens system for microscopes, and more specifically an objective lens system consisting of four lens components and having a long working distance and a large numerical aperture.
(B) Description of the Prior Art
As plan objective lens systems for microscopes, there have conventionally been known those which comprise two doublet lens components or four lens elements, etc. Most of the conventional low magnification objective lens systems of this type for microscopes had small N.A. of about 0.1 and working distances of about 0.2 when converted into distances corresponding to f=1. Further, these objective lens systems for microscopes were not satisfactory from a viewpoint of correction of aberrations since coma could not be corrected favorably and relatively large astigmatic differences remained in these objective lens systems for microscopes.